Lyophilized or freeze-dried products such as medical products typically are stored in Type 1 glass containers or vials, which have very low moisture vapor transmission rates that keep the lyophilized cake intact. Plastic containers, although less expensive and more rugged than glass containers, typically have not been employed for storing lyophilized products because of the higher moisture vapor transmission rates of typical plastic containers. A general object of the present disclosure is to provide a plastic container suitable for long-term storage of lyophilized products, and to provide a method of storing lyophilized products in such a container.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A multilayer plastic container for storing lyophilized products, in accordance with one aspect of the present disclosure, includes at least three layers consisting of inner and outer layers having a moisture vapor transmission rate of not more than 0.1 gm mil/100 sq. in.-day at 73° F. and 95% rh, and an intermediate layer of hygroscopic resin construction having a moisture content less than 1000 ppm. The hygroscopic intermediate layer preferably comprises at least 30% of the total thickness of the three layers. The inner and outer layers preferably are of cyclic olefin polymer or cyclic olefin copolymer construction, and the hygroscopic intermediate layer preferably is of amorphous nylon construction. The container preferably is empty and sealed within a secondary container, such as a metallized bag, that is impervious to moisture.
A method of storing a lyophilized product, in accordance with a second aspect of the present disclosure, includes providing a multilayer plastic container having first and second layers with moisture vapor transmission rates of not more than 0.1 gm mil/100 sq. in.-day at 73° F. and 95% rh, and a third layer between the first and second layers of hygroscopic plastic construction having a moisture content of less than 1000 ppm. The multilayer plastic container is stored in a low humidity environment, such as within a sealed metallized bag. At the time of use, the container is removed from the low humidity environment, a product is placed within the container and the product is lyophilized. The hygroscopic third layer of the container functions as a desiccant to absorb any moisture transmitted through the first and second layers.